1. Field of the Invention
The invention relates to polymer blends of poly(meth)-acrylates and ABS polymerizates, with improved thermal and mechanical properties, which are high strength materials that can be processed like a thermoplastic.
2. Description of the Prior Art
Polymethacrylates, both methylmethacrylate-homopolymers and -copolymers and acrylonitrile-butadiene-styrene (ABS) polymers are used widely in industry as polymers that can be processed like a thermoplastic. Blends of these two kinds of polymers are also industrially interesting combinations and could yield other interesting and useful blends, if specific thermal properties such as the softening temperature and the mechanical properties, primarily the notched impact strength, were improved. The need for such polymers exists, for example, for the manufacture of highly stressed moulded parts, in the construction of vehicles.
Thermoplastic compositions are known from the German Auslegeschrift 12 63 295; which discloses blends of polymers, and, in particular, an ABS polymer with subordinate quantities of a polymethylmethacrylate or a copolymer with at least 70 percent by weight of methylmethacrylate.
In European Published Patent Application 0 037 686 (equivalent to U.S. Pat. No. 4,440,905), thermoplastic blends comprising an elastomeric impact strength modifying polymer, e.g., an ABS polymer, in addition to another polymeric auxiliary agent, and one or more rigid matrix polymers such as methylmethacrylate-homopolymers and -copolymers or polycarbonate are claimed without detailed information.
Blends of a styrene-rich copolymerizate with ABS and/or MABS polymers and polycarbonate are described in European Published Patent Application 0 135 492 (equivalent to U.S. Pat. No. 4,663,389).
In German Offenlegungsschrift 32 38 228 (equivalent to U.S. Pat. No. 4,390,657), a thermoplastic composition is claimed that includes a polycarbonate resin, a copolymer comprising acrylonitrile, butadiene and an alkenyl aromatic compound like styrene, thus an ABS polymer, and a C.sub.1 -to C.sub.5 -acrylate or -methacrylate-interpolymer. The moulding composition contains a predominant amount of polycarbonate and small amounts of the acrylate-/methacrylate-interpolymer, i.e. a methacrylate polymer grafted on an acrylate rubber.
U.S. Pat. No. 4,667,162 describes a thermoplastic moulding composition comprising polycarbonate resin, an ABS polymer and an impact modifier based on acrylic rubber.
The specified prior art shows that the known blends of this kind always contain high percentages of styrene-rich polymerizates and/or high percentages of polycarbonate, wherein these polymer blends represent industrial compounds with poor weathering resistance, and in the case of a high polycarbonate content also poor flow and thus relatively high processing temperature.